Continuous bow closure for hydrofoil boat

ABSTRACT

A continuous closure for the slotted bow opening for hydrofoils employing a forward bow strut which protrudes from the bow in the extended (vertical) position and is adapted to swing to a forward protruding retracted (horizontal) position, and vice versa. The closure is an elongated panel structure, having a double function, that of performing as a bow and as a closure of the bow slot at all times. One portion of the panel is deployed at the forward and one portion at the aft of the strut. Depending on strut position, the forward or the aft portion of the panel are stored in the bow area or perform as bow and bow closure for the boat.

[451 Nov, 26, 1974 CONTINUOUS BOW CLOSURE FOR HYDROFOIL BOAT [75] Inventor: Nicolaas De Vogel, Mercer Island,

Wash.

[73] Assignee: The Boeing Company, Seattle,

Wash.

22 Filed: Sept. 28, 1973 21 Appl. No.: 401,787

FOREIGN PATENTS OR APPLICATIONS 441,084 l/1936 Great Britain 160/122 Primary ExaminerTrygve M. Blix Assistant Examiner-Barry L. Kelmachter Attorney, Agent, or FirmNicolaas DeVogel; Kenneth W. Thomas ABSTRACT A continuous closure for the slotted bow opening for hydrofoils employing a forward bow strut which protrudes from the bow in the extended (vertical) position and is adapted to swing to a forward protruding retracted (horizontal) position, and vice versa. The closure is an elongated panel structure, having a double function, that of performing as a bow and as a closure of the bow slot at all times. One portion of the panel is deployed at the forward and one portion at the aft of the strut. Depending on strut position, the forward or the aft portion of the panel are stored in the bow area or perform as bow and bow closure for the boat.

11 Claims, 16 Drawing Figures PATENTEL 3,850,129

sum 1 or a ll ix mi:

PATENTELHUVZBIBM 3.850, 1 2 sum 2m a PATENIEL HI]? 2 6 I974 Sumatra CONTINUOUS BOW CLOSURE FOR HYDROFOIL BOAT BACKGROUND OF THE INVENTION a. Field of the Invention The present invention relates to closure means and more particularly to a bowdoor for marine, air and surface vessels.

b. Description of the Prior Art There was no reference patent nor literature found which disclosed the concept of the present invention.

The present day hydrofoil boats which employ a forward retractable strut such as the US. Navy PHM, PGH2, Tucumcari, and the Boeing commercial hydrofoil boat 929, as described and illustrated in US. Pat. No. 3,745,959, either maintain a forward open bow slot or cover the bow slot partially by overlapping doors such as shown in US. Pat. application Ser. No. 373,549. The partial bow closure by doors, as disclosed in the above application, provides for reduced drag during the hull-borne and the foil-borne operation of the boat versus the open bow slot system. Of course, a complete closure of the bow slot would provide for the most efficient operation, and, accordingly, the present concept discloses a complete bow closure means which continuously exists regardless of the strut position.

SUMMARY OF THE INVENTION Hydrofoil boats using the canard" foil area distribution system require a most forwardly located short span foil design, which preferably is carried by one strut.

If the boat is designed for average harbor depth operations, a fixed downwardly extending strut becomes hazardous and accordingly the designer has to provide for a retractable strut located at the bow. The next problem that presents itself is the retraction system. A vertical upward strut movement for storage purposes does not clear the foil from its submerged condition and because the foil is an accurately designed and manufactured wing with smooth surfaces, which serves as the important lift means for the boat, the foils should be protected from any possible damage and thus a complete retraction out of the water is preferred.

By simply pivoting the strut about a horizontal axis, a bow opening having a slot configuration is required. Of course, the bow ofa ship should be smooth and preferably pointed in order to reduce drag, and the provision of a slot at the how will cause the opposite effect.

The provision of bow doors do reduce the drag problem by a large amount; however, the bow doors do not completely cover the slot since the upper and the most lower bow area should stay open for strut protrusion. Some hydrofoil boat configurations using the canard system have an open bow slot which remains open. However, those types of boats are relatively small, and as soon as a larger type of boat, e.g., over l-ton displacement, is used, the propulsion power should be high enough to cause the sufficient speed for the foils to require the lift for getting foil borne. Therefore, a bow slot would become a serious speed reducer and the closure of the slot is thus recommended.

Since bow doors are only partly solving the problem, a complete closure means of the bow during take-off from hull-borne to foil-borne operations is recommended. Also, such a complete bow closure would be advantageous during foil-borne operations in reducing wind drag and during hull operations by avoiding floating contaminants, logs, weeds, etc, to enter the slot and to promote harbor navigation.

Consequently, the present invention provides for a closure means of the bow slot which is completely covering the bow slot and serves as a bow to the hydrofoil boat. Also, the forward strut is capable of unrestricted movement from retracted to extended position, and vice vera, without opening the bow slot which is accomplished by having the closure means in a sliding panel type configuration arranged such that the closure means slides with the movement of the strut in the bow area so that alternately one part is used as a slot closure while the other part is stored.

It is therefore an object of the present invention to provide for a continuous bow closure means for hydrofoil boats which serves as a bow and closure during the forward strut retracted and extended position.

Another object of the invention is to provide a closure for the bow which completely fills the entire opening for a'retractable forward strut and serves as a bow in the hull-borne and foil-borne boat operations.

A further object of the invention is to keep the bow of the boat at foiland hull-borne operations closed so that a dragless, streamlined bow is maintained, and debris and other contaminants are prevented from entering the bow area.

In general, there is presented an unique continuous bow closure means for hydrofoil boats having a retractable strut foil apparatus at the bow which requires a hull provided with a slotted bow opening. Furthermore, there is required a strut member protruding through the opening and arranged to pivot from a first to a second protruding position which while moving activates the continuous bow closure means provided about the strut member at the strut protruding opening intersection and arranged to move in coordination with the strut member for retaining closure of the bow slotted opening when the bow member is in the first position, moves to the second and is in the second position.

Other objects and many of the attendant advantages of this invention will be readily'appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof.

In the Drawings:

FIG. 1 is a perspective illustration of a hydrofoil boat with a forward bow strut during foil-borne operation. The illustration displays the continuous bow closure concept as visualized per present invention.

FIG. 2 is a vertical cross-section of the bow with the strut in its extended position.

FIG. 3 is the same section as shown in FIG. 2 but with the strut in the retracted position.

FIG. 4 is a perpendicular section of the continuous bow closure means taken on theline 44 of FIG. 2.

FIG. 5 is an enlarged detail of the continuous bow closure means at the bow slot as used in FIGS. 2 and 3.

FIG. 6 is an enlarged detail of the continuous bow closure means at the guide rail turning area towards the storage means, as indicated in FIGS. 2 and 3, respectively.

portion scoping configuration.

FIG. 12 is a vertical cross-section of the bow portion of a hydrofoil boat presenting a fourth embodiment of the present invention.

FIG. 13 is a perspective view of the continuous bow closure means as shown in FIG. 12.

FIGS. 14 and 15 are sections of the continuous bow closure means taken along line 14-14 and 15-15 of FIG. 12.

FIG. 16 is an enlarged detail of the coordination of the strut and bow closure sleeve means in the retracted and extended strut position as per FIG. 12.

DESCRIPTION AND OPERATION OF THE INVENTION With reference to the drawings, there is illustrated in FIG. I a hydrofoil boat 20 of the canard strut type arrangement being foilborne and approaching the viewer. The boat has a forward strut 22 and an aft strut arrangement comprising a starboard and port strut connected with a submerged horizontally positioned foilwing (not visible).

The aft strut arrangement and the forward strut 22 are retractable as follows: the aft strut arrangement pivots rearwards so that the wing foil is completely lifted out of the water above the aft deck, and the forward strut 22 pivots forward from the extended position to a position where the foil is above the forward deck. It should be emphasized that the words retracting and extending for indicating the strut position is the terminology used by the persons skilled in the hydrofoil art.

To enable the positioningof the strut and foils from the extended to the retracted positions in the manner required, a slotted opening in the hull at the bow line is necessary and unavoidable. As is well known, the bow of a boat needs to be closed and preferably pointed so that drag is minimized. As illustrated in FIG. I, the slot is closed completely by a continuous bow closure 24 which acts as a bow and reduces drag when hulland foil-borne. The continuous bow closure means 24 can be accomplished by various unique embodiments disclosed hereinafter. Under the terminology of drag" as used herein, it should be understood in general that the word drag means the force exerted on the hydrofoil boat which tends to reduce its forward motion.

Referring now to FIGS. 2 through 6, there is shown a bow portion with a continuous closure means which is made up of a plurality of hingeable sections 42 which are connected to the strut 22 at the strut/hull protruding intersection by a sleeve means 44 which is permanently or slidably arranged about the strut 22. Continuous closure means 40 comprises a first, second and third closure portions 46, 48 and 50, respectively. The first portion 46 closes the slot when the strut 22 is extended during foil-borne operations, and the third portion 50 closes the slot when the strut 22 is extracted during the hull-borne condition. The hingeable sections 42 are provided with sliding or rolling means 52 or the like which are guided by a rail means 54 employed in the forward bow area of the boat. When the first portion 46 closes the slot, the third portion 50 of the continuous closure means 40 is stored on the rail 54 in the storage means or area 58. In the strut retracted position, the first portion 46 is stored in a similar storage area 56 as shown in FIG. 3. As illustrated in FIGS. 4- 6, the hingeable sections 42 telescope into each other to form a continuous bow closure structure 40 similar to a watch band. The second portion 48 comprises the sleeve 44 which may be fixedly engaged to the strut 22 in the event that the strut 22 internal pivot radius is equal in the extended and the retracted strut 22 position. Otherwise, it would be necessary to provide a slidable engagement between the sleeve 44 and the strut 22, as shown in FIGS. 2 and 3. The forces which are experienced by a bow are very large so that a strong sturdy structure is required. The hingeable sections 42 have an inherent solid strength by their triangular configuration which is enhanced by the overlapping or telescoping position with one another.

A very simple embodiment of a continuous closure is shown in FIGS. 7-10 where a flat sheet material 60 is used, similar to the protection sheets in rotating gun turrets, as a continuous closure means 60.

During hull-borne operations, the area 64 (FIG. 8) endures the heaviest bow loads, and during foil-borne operations, the area 66 (FIG. 7) may endure heavy bow loads. To assure that the continuous closure means 60 which serves as a bow is able to accept the very high loads, the strut 22 is provided with an internal wide base 62 that engages with the continuous closure means for providing the necessary support. The engagement may be a permanent connection or could be a contacting connection, depending on the strut pivot radius and hull bow design. FIGS. 9 and 10 are sections showing the flat continuous closure means 60 guided by the bearing means 68 while providing passage of the strut 22 from the retracted to the extended position, and vice versa. The areas 67 and 69 represent guided storage means for the closure means 60.

FIG. 11 shows basically another embodiment of a continuous closure means 70 which instead of using a rolled-up or guided storage system relies on a stacked up storage means 72 having slidable bow panels 74 telescoping from the storage means 72 through the bow slot so that an ever continuous closure 70 is accomplished. I

FIGS; 12 through l6 illustrate a fourth embodiment of a continuous closure means which is'more sophisticated and basically uses guide roller sets 82 which also form the flat-shaped continuous closure 80 into a bow shape at the required bow area (FIG. 15). The means 80 is preferably made of a spring-type of steel which immediately returns to its original fiat shape and further possesses the ability to be rolled up into storage drums 86 and S8. The sleeve 84 is illustrated in FIG. 16 to be slidably engaged about the strut 22. The sleeve 84 position is shownin solid lines for representing the extended strut position and in phantom lines for representing the sleeve position in the retracted position. The foregoing embodiments show various'types of storage means for the continuous closure means and also different sleeve engagements or intersections between the strut 22 and the closure means; however, it should be understood that many other ways, familiar to the person skilled in the art, can be found.

In general, it is the intention that the drag problem at the open bow-slot, which exists on hydrofoil boats of the canard single forward strut type is solved by the hereinbefore described unique and novel concept and apparatus.

Accordingly, although a couple of arrangements of the invention have been illustrated above by way of example, it is not intended that the invention be limited thereto. Accordingly, the invention should be consid ered to include any and all modifications, alterations or equivalent arrangements falling within the scope of the annexed claims.

Now, therefor, I claim:

1. A continuous'strut-hull closure means for hydrofoil boats employing retractable struts, comprising in combination:

a. strut means pivotally mounted and supported within said hydrofoil hull and adapted to rotate along one defined are about said strut means pivot support from a hydrofoil boat hull-borne strut retracted position towards a hydrofoil foil-borne strut extended position, and vice versa;

b. said hull provided with a slot, which is disposed parallel to an imaginary line connecting gunwale to keel, to accomplish strut/hull protrusion and strut arc movement through said slot length between said retracted position to said extended position, and

c. an elongated closure means, slidably arranged in said slot for continuously complementing and closing said slot, comprising a first, second and third portion wherein said second portion is engaged about said strut at said strut/hull protrusion and wherein said third portion closes said slot in said strut retracted position and said first portion closes said slot in said strut extended position.

2. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1 wherein said elongated closure means comprises a plurality of hingeable and telescoping sections having a triangular cross-sectional configuration.

3. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 2 wherein said elongated closure means is supported by a plurality of guide bearing and rail means arranged in said slot.

4.'A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1, wherein said elongated closure means comprises a flat sheet material being supported by bearing means mounted in said slot and wherein said strut has a wide base portion in contact with said closure means at said second portion so that support is provided to said closure means against external high loads.

5. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 4, wherein said hull is provided with storage means adapted to guide said elongated closure means of flat sheet material next to said slot so that said first portion is stored while said third portion provides closure of said slot in said strut retracted position and said third portion is stored while said first portion provides closure of said slot in said strut extended position.

6. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1, wherein said elongated closure means first and third portions comprises a plurality of slidable panels disposed in telescoping engagement with one another and wherein said hull is provided with storage means for holding said panels of said first and said third portions in stacked-up storage condition during said strut retracted position and said strut extended position, respectively.

7. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1, wherein said elongated closure means comprises a flat-shaped spring material and wherein said slot is provided with guide roller means for providing moveable guidance support and for forming said closure means into hull complementing shape at specific hull areas.

8. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 7, wherein said hull is provided with storage drums for storing said closure means of flat spring-type material in rolled-up condition during said strut retracted position and said strut extended position, respectively.

9. Continuous closure means for hydrofoil boats having retractable strut-foil apparatus comprising in combination a. a hull provided with a slot;

b. a strut member pivotally supported within said hull and protruding through said slot and arranged to pivot about said strut member pivot support for travel through said slot length from a first strut retracted position to a second strut extended position and vice versa, and articulated flexible closure means having a substantial triangular cross-sectional configuration, disposed in and complementing with said slot, said strut member engaged with said closure means and arranged to move in coordination with said closure means for retaining closure of said slot in'said hull when said strut member is in said first position, moves to said second position and is in said second position and vice versa.

10. Continuous closure means as claimed in claim 9 wherein said closure means of triangular crosssectional configuration comprises a plurality of hingeable telescoping sections supported by a plurality of guide-bearing and rail means mounted in said hull.

11. A continuous closure means as claimed in claim retracted position. 

1. A continuous strut-hull closure means for hydrofoil boats employing retractable struts, comprising in combination: a. strut means pivotally mounted and supported within said hydrofoil hull and adapted to rotate along one defined arc about said strut means pivot support from a hydrofoil boat hull-borne strut retracted position towards a hydrofoil foilborne strut extended position, and vice versa; b. said hull provided with a slot, which is disposed parallel to an imaginary line connecting gunwale to keel, to accomplish strut/hull protrusion and strut arc movement through said slot length between said retracted position to said extended position, and c. an elOngated closure means, slidably arranged in said slot for continuously complementing and closing said slot, comprising a first, second and third portion wherein said second portion is engaged about said strut at said strut/hull protrusion and wherein said third portion closes said slot in said strut retracted position and said first portion closes said slot in said strut extended position.
 2. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1 wherein said elongated closure means comprises a plurality of hingeable and telescoping sections having a triangular cross-sectional configuration.
 3. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 2 wherein said elongated closure means is supported by a plurality of guide bearing and rail means arranged in said slot.
 4. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1, wherein said elongated closure means comprises a flat sheet material being supported by bearing means mounted in said slot and wherein said strut has a wide base portion in contact with said closure means at said second portion so that support is provided to said closure means against external high loads.
 5. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 4, wherein said hull is provided with storage means adapted to guide said elongated closure means of flat sheet material next to said slot so that said first portion is stored while said third portion provides closure of said slot in said strut retracted position and said third portion is stored while said first portion provides closure of said slot in said strut extended position.
 6. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1, wherein said elongated closure means first and third portions comprises a plurality of slidable panels disposed in telescoping engagement with one another and wherein said hull is provided with storage means for holding said panels of said first and said third portions in stacked-up storage condition during said strut retracted position and said strut extended position, respectively.
 7. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 1, wherein said elongated closure means comprises a flat-shaped spring material and wherein said slot is provided with guide roller means for providing moveable guidance support and for forming said closure means into hull complementing shape at specific hull areas.
 8. A continuous strut/hull closure means for hydrofoil boats employing retractable struts as claimed in claim 7, wherein said hull is provided with storage drums for storing said closure means of flat spring-type material in rolled-up condition during said strut retracted position and said strut extended position, respectively.
 9. Continuous closure means for hydrofoil boats having retractable strut-foil apparatus comprising in combination a. a hull provided with a slot; b. a strut member pivotally supported within said hull and protruding through said slot and arranged to pivot about said strut member pivot support for travel through said slot length from a first strut retracted position to a second strut extended position and vice versa, and c. articulated flexible closure means having a substantial triangular cross-sectional configuration, disposed in and complementing with said slot, said strut member engaged with said closure means and arranged to move in coordination with said closure means for retaining closure of said slot in said hull when said strut member is in said first position, moves to said second position and is in said second position and vice versa.
 10. Continuous closure means as claimed in claim 9 wherein said closure means of triangular cross-sectional configuration comprises a plurality of hingeable telescoping sections supported by a plurality of guide-bearing and rail means mounted in said hull.
 11. A continuous closure means as claimed in claim 10 wherein a portion of said closure is stored on said rail means into storage means located in said hull area during said strut-extended position and said strut-retracted position. 